Shot peening basket



May 23, 1961 L. c. BIXBY SHOT PEENING BASKET- Filed May 5, 1958 INVENTOR LEON C. BIA 5V United States Patent SHOT PEENING BASKET Leon C. Bixby, Fairgrounds Road, Wellington, Ohio Filed May 5, 1958, Ser. No. 733,195 1 Claim. (Cl. 51--13) This invention relates to improvements in shot peening baskets and more particularly to the use of ferrous alloys including manganese in the fabrication of shot peening baskets.

The shot peening process is one in which iron castings and the like are cleaned. In this process, the castings are tumbled in a drum-like basket while simultaneously steel shot is hurled in a dense, high velocity stream through the walls of the basket against the castings. The basket is fabricated from an open mesh lattice of metallic wire elements, the openings in the lattice being large enough that a comparatively small area is presented to the incoming stream of steel shot, yet small enough that the castings tumbled within the basket cannot escape from the basket.

conventionally, the basket is rotated in a transverse stream of steel shot, the shot impinging repeatedly on the wire elements forming the open mesh lattice of the basket. It is a necessary consequence of this repeated peening of the wire elements in the basket that the wire elements will become heavily abraded and eventually will break.

An object of this invention is to provide a shot peening basket having an improved life wherein the basket has an open mesh lattice fabricated from wire elements which are an alloy of manganese.

Other objects and advantages reside in the construction of parts, the combination thereof, the method of manufacture and the mode of operation, as will become more apparent from the following description.

In the drawing,

Figure 1 is a perspective view of a shot peening basket with parts broken away to reveal structural detail.

Figure 2 is an enlarged fragmentary sectional view taken substantially along the line 2-2 of Figure 1.

Figure 3 is an enlarged fragmentary sectional view taken substantially along the line 3-3 of Figure 1.

Referring to the drawing in detail, the shot peening basket of Figure 1 includes a rectangular lattice of parallel annular support rods 12 and transverse wire elements 16. As best illustrated in Figure 3, the wire elements 12 are provided with oppositely threaded ends 13 joined by a union nut 14. The support rods 12 are thus annular hoops. The wire elements 16 are formed with spaced loops 18 through which the support rods are passed.

In constructing the lattice for the basket, the loops 18 space the annular support rods 12 equally along the length of the basket. Annular spacer elements 20 encircling the support rods 12 space the wire elements 16 equally along the periphery of the basket. A cylindrical lattice structure having rectangular openings therein is thus formed.

The ends of the cylindrical lattice formed by the support rods 12 and wire elements 16 are closed by plates 22 and 24. These plates are attached to the lattice structure in the following manner. At the extreme ends of the cylindrical lattice structure, alternate spacer elements on the support rods 12 are provided with a flat side. These flat sided spacer elements, best seen in Figure 2, are designated by the reference numeral 26. The end plates 22 and 24 are each provided along the margin thereof with apertures 27 spaced apart a distance corresponding to the spacing between the flat sided spacer elements 26 of the cylindrical lattice structure. Threaded screws 28 passing through the apertures 27 threadedly engage the spacer elements 26, thus securing the end plates to the cylindrical lattice structure.

A door to the interior of the basket is provided as follows. A pintle 29 is fixedly secured in an axial position to the end plate 22. Journalled for rotation on the pintle 29 on the exterior side of the end plate 22 is a semicircular plate 30. Complementing this plate 30 is a semicircular opening 32 in the plate 22. The arrangement is such that rotation of the plate 30 may be used to selectively open or close the opening 32 in the plate 22.

Provision is made for locking the plate 30 relative to the plate 22 as follows. An aperture 36 is located in the plate 22. In a projections 34 in the plate 30 an aperture 38 is located. This arrangement is such that the apertures 36 and 38 are aligned when the plate 30 fully closes the opening 32 in the plate 22. A retaining pin 40 projected through the aligned apertures 36 and 38 serves to lock the plate 30 in the closed position.

In constructing the shot peening basket as described in the foregoing, steel is used throughout with the excep tion of the wire elements 16. The wire elements 16 are fabricated with a manganese alloy. It is found that manganese alloy wire elements have exceptional durability in this particular application. This is believed due to the characteristic of manganese that it hardens upon repeated impact as occurs in the shot peening process.

In the preferred embodiment of this invention the Wire elements 16 are constructed from Manganol which is an alloy of steel with 13% manganese and 5% nickel by weight. While the preferred embodiment uses 13% manganese beneficial results are obtainable throughout the range of manganese concentrations between 10% and 15% by weight.

Although the preferred embodiment of the device has been described, it will be understood that within the purview of this invention various changes may be made in the form, details, proportion and arrangement of parts, the combination thereof and mode of operation, which generally stated consist in a device capable of carrying out the objects set forth, as disclosed and defined in the appended claim.

Having thus described my invention, I claim:

A tumbling drum for use in tumbling iron castings and the like which are to be shot peened in a process wherein steel shot is hurled at high velocity through the walls of the drum to impinge upon the castings, said drum comprising an open mesh lattice of parallel wire elements and transverse support rods, said support rods being substantially circular so as to support said lattice in the shape of a cylindrical drum, a substantially circular end plate secured to and enclosing each end of said lattice, and a pintle mounted centrally on each end plate and projecting axially and outwardly therefrom to adapt the drum for rotary movement, said wire elements having loops therein encircling the support rods and being fabricated from an initially unhardened steel alloy including 10% to 15 manganese by weight, the drum having the characteristic that when placed into use the manganese steel wire elements are hardened through the peening action of the steel shot.

References Cited in the file of this patent UNITED STATES PATENTS 974,165 Mascia Nov. 1, 1910 1,784,865 Fahrenwald Dec. 16, 1930 2,752,732 Walker July 3, 1956 

